1. Field of the Invention
The present invention relates to a storage system and storage migration method that are particularly suited to application to a storage system requiring storage migration.
2. Description of Related Art
In recent years, storage systems handling massive amounts of data manage data using large capacity storage apparatuses provided separately from host apparatuses.
With this kind of storage system, it is necessary to transfer an access destination of a host apparatus to a new storage apparatus or to another storage apparatus at the time of the introduction of a new storage apparatus or while clustering a storage apparatus and migrating to another storage apparatus. In this event, it is preferable for migration of the access destination of this host apparatus to take place without transfer of data between the host apparatus and the storage apparatus stopping, and while maintaining the function of the storage apparatus.
Technology for saving vast amounts of data that has exceeded the system lifetime is disclosed in patent document 1. According to this patent document, technology is disclosed where, in order to replace storage apparatuses (hereinafter referred to as migration source storage apparatuses) to which technology for connecting external storage is applied with other storage apparatuses (hereinafter referred to as migration destination storage apparatuses), data stored in logical units in the possession of the migration source storage apparatuses is copied to logical units in the possession of migration destination storage apparatus so as to achieve migration.
[Patent Document 1]
Japanese Patent Laid-open Publication No. 2005-011277.
However, in the event of migrating an access destination accessed by a host apparatus to a new storage apparatus, with the existing mechanism, this involves operations such as the replacing of cables, and resulting in the problem that the exchange of data between the host apparatus and the storage apparatus is therefore temporarily stopped.
Further, in the event of carrying out migration to an access destination for a certain host apparatus between storage apparatuses (between old models and new models of storage apparatuses of the same vendor, or between storage apparatuses where the vendor is different) of different types, situations where it is necessary to change microprograms on the side of the storage apparatus before migration are common, and changes in processing to perform migration are therefore troublesome.
Moreover, there is also the possibility of, for example, deterioration occurring as the result of excessive loads being applied to the side of the migration source storage apparatus as a result of falling in the processing performance of input/output processing etc. occurring on the side of the migration source storage apparatus, while carrying out processing to copy from the logical units of the migration source to the logical units of the migration destination.
In order to take the above points into consideration, the present invention proposes a storage system and storage migration method where migration may be carried out to an access destination of a host apparatus without stopping the exchange of data between the host apparatus and the storage apparatus, and while continuing the functions of the storage apparatus.